feat(io): add bulk delete API to FileIO. (#659)

## Summary

Add a new `FileIO::DeleteFiles(...)` API as a bulk deletion entry point.

The default implementation deletes files sequentially by calling the
existing
`DeleteFile(...)` method and returns the first deletion error
encountered.

This PR only adds the API and backward-compatible fallback behavior. It
does not
yet update `ExpireSnapshots` to use `DeleteFiles(...)`, and it does not
introduce
parallel deletion.

Fixed: #658 

## Motivation

`ExpireSnapshots` and other cleanup flows may need to delete many files.
A
bulk deletion API gives FileIO implementations a common extension point
for
future optimized deletion strategies, such as storage-native batch
deletion or
parallel fallback deletion.

Author: slfan1989

src/iceberg/arrow/arrow_io.cc

@@ -22,6 +22,7 @@
 #include <limits>
 #include <mutex>
 #include <optional>
+#include <vector>
 
 #include <arrow/buffer.h>
 #include <arrow/filesystem/localfs.h>
@@ -568,6 +569,18 @@ Status ArrowFileSystemFileIO::DeleteFile(const std::string& file_location) {
   return {};
 }
 
+Status ArrowFileSystemFileIO::DeleteFiles(
+    const std::vector<std::string>& file_locations) {
+  std::vector<std::string> paths;
+  paths.reserve(file_locations.size());
+  for (const auto& file_location : file_locations) {
+    ICEBERG_ASSIGN_OR_RAISE(auto path, ResolvePath(file_location));
+    paths.push_back(std::move(path));
+  }
+  ICEBERG_ARROW_RETURN_NOT_OK(arrow_fs_->DeleteFiles(paths));
+  return {};
+}
+
 std::unique_ptr<FileIO> ArrowFileSystemFileIO::MakeMockFileIO() {
   return std::make_unique<ArrowFileSystemFileIO>(
       std::make_shared<::arrow::fs::internal::MockFileSystem>(

src/iceberg/arrow/arrow_io_internal.h

@@ -23,6 +23,7 @@
 #include <memory>
 #include <optional>
 #include <string>
+#include <vector>
 
 #include <arrow/filesystem/type_fwd.h>
 #include <arrow/io/type_fwd.h>
@@ -77,6 +78,9 @@ class ICEBERG_BUNDLE_EXPORT ArrowFileSystemFileIO : public FileIO {
   /// \brief Delete a file at the given location.
   Status DeleteFile(const std::string& file_location) override;
 
+  /// \brief Delete files at the given locations.
+  Status DeleteFiles(const std::vector<std::string>& file_locations) override;
+
   /// \brief Get the Arrow file system.
   const std::shared_ptr<::arrow::fs::FileSystem>& fs() const { return arrow_fs_; }
 

src/iceberg/file_io.cc

@@ -100,4 +100,11 @@ Status FileIO::WriteFile(const std::string& file_location, std::string_view cont
   return FinishWithCloseStatus(std::move(status), stream->Close());
 }
 
+Status FileIO::DeleteFiles(const std::vector<std::string>& file_locations) {
+  for (const auto& file_location : file_locations) {
+    ICEBERG_RETURN_UNEXPECTED(DeleteFile(file_location));
+  }
+  return {};
+}
+
 }  // namespace iceberg

src/iceberg/file_io.h

@@ -26,6 +26,7 @@
 #include <span>
 #include <string>
 #include <string_view>
+#include <vector>
 
 #include "iceberg/iceberg_export.h"
 #include "iceberg/result.h"
@@ -154,6 +155,16 @@ class ICEBERG_EXPORT FileIO {
   virtual Status DeleteFile(const std::string& file_location) {
     return NotImplemented("DeleteFile not implemented");
   }
+
+  /// \brief Delete files at the given locations.
+  ///
+  /// Implementations that can delete multiple files efficiently should override this
+  /// method. The default implementation deletes files sequentially using DeleteFile
+  /// and returns the first error encountered.
+  ///
+  /// \param file_locations The locations of the files to delete.
+  /// \return void if all deletes succeed, or an error code if any delete fails.
+  virtual Status DeleteFiles(const std::vector<std::string>& file_locations);
 };
 
 }  // namespace iceberg

src/iceberg/test/CMakeLists.txt

@@ -124,6 +124,7 @@ add_iceberg_test(util_test
                  data_file_set_test.cc
                  decimal_test.cc
                  endian_test.cc
+                 file_io_test.cc
                  formatter_test.cc
                  lazy_test.cc
                  location_util_test.cc

src/iceberg/test/arrow_io_test.cc

@@ -21,6 +21,7 @@
 #include <array>
 #include <memory>
 #include <string>
+#include <vector>
 
 #include <arrow/filesystem/localfs.h>
 #include <arrow/result.h>
@@ -341,6 +342,20 @@ TEST_F(LocalFileIOTest, DeleteFile) {
   EXPECT_THAT(del_res, HasErrorMessage("Cannot delete file"));
 }
 
+TEST_F(LocalFileIOTest, DeleteFiles) {
+  auto first_path = CreateNewTempFilePath();
+  auto second_path = CreateNewTempFilePath();
+  ASSERT_THAT(file_io_->WriteFile(first_path, "hello"), IsOk());
+  ASSERT_THAT(file_io_->WriteFile(second_path, "world"), IsOk());
+
+  std::vector<std::string> paths = {first_path, second_path};
+  EXPECT_THAT(file_io_->DeleteFiles(paths), IsOk());
+
+  EXPECT_THAT(file_io_->ReadFile(first_path, std::nullopt), IsError(ErrorKind::kIOError));
+  EXPECT_THAT(file_io_->ReadFile(second_path, std::nullopt),
+              IsError(ErrorKind::kIOError));
+}
+
 void VerifyReadFullyReadsFromAbsolutePosition(const std::shared_ptr<FileIO>& file_io,
                                               const std::string& path) {
   ASSERT_THAT(file_io->WriteFile(path, "abcdef"), IsOk());

src/iceberg/test/file_io_test.cc

@@ -0,0 +1,75 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+#include "iceberg/file_io.h"
+
+#include <string>
+#include <utility>
+#include <vector>
+
+#include <gtest/gtest.h>
+
+#include "iceberg/test/matchers.h"
+
+namespace iceberg {
+namespace {
+
+class RecordingFileIO : public FileIO {
+ public:
+  explicit RecordingFileIO(std::string failure_path = "")
+      : failure_path_(std::move(failure_path)) {}
+
+  Status DeleteFile(const std::string& file_location) override {
+    deleted_paths.push_back(file_location);
+    if (file_location == failure_path_) {
+      return IOError("failed to delete {}", file_location);
+    }
+    return {};
+  }
+
+  std::vector<std::string> deleted_paths;
+
+ private:
+  std::string failure_path_;
+};
+
+}  // namespace
+
+TEST(FileIOTest, DeleteFilesFallsBackToDeleteFileForEachPath) {
+  RecordingFileIO file_io;
+  std::vector<std::string> paths = {"file-a.avro", "file-b.avro"};
+
+  EXPECT_THAT(file_io.DeleteFiles(paths), IsOk());
+  EXPECT_THAT(file_io.deleted_paths,
+              ::testing::ElementsAre("file-a.avro", "file-b.avro"));
+}
+
+TEST(FileIOTest, DeleteFilesReturnsFirstDeleteFileError) {
+  RecordingFileIO file_io("file-b.avro");
+  std::vector<std::string> paths = {"file-a.avro", "file-b.avro", "file-c.avro"};
+
+  auto status = file_io.DeleteFiles(paths);
+
+  EXPECT_THAT(status, IsError(ErrorKind::kIOError));
+  EXPECT_THAT(status, HasErrorMessage("failed to delete file-b.avro"));
+  EXPECT_THAT(file_io.deleted_paths,
+              ::testing::ElementsAre("file-a.avro", "file-b.avro"));
+}
+
+}  // namespace iceberg

src/iceberg/test/meson.build

@@ -88,6 +88,7 @@ iceberg_tests = {
             'data_file_set_test.cc',
             'decimal_test.cc',
             'endian_test.cc',
+            'file_io_test.cc',
             'formatter_test.cc',
             'lazy_test.cc',
             'location_util_test.cc',

src/iceberg/update/expire_snapshots.cc

@@ -98,26 +98,22 @@ class FileCleanupStrategy {
     return expired;
   }
 
-  /// \brief Delete a single file
-  void DeleteFile(const std::string& path) {
+  /// \brief Delete files at the given locations.
+  void DeleteFiles(const std::unordered_set<std::string>& paths) {
     try {
       if (delete_func_) {
-        delete_func_(path);
+        for (const auto& path : paths) {
+          delete_func_(path);
+        }
       } else {
-        std::ignore = file_io_->DeleteFile(path);
+        std::vector<std::string> path_list(paths.begin(), paths.end());
+        std::ignore = file_io_->DeleteFiles(path_list);
       }
     } catch (...) {
       // TODO(shangxinli): add retry
     }
   }
 
-  // TODO(shangxinli): Add bulk deletion
-  void DeleteFiles(const std::unordered_set<std::string>& paths) {
-    for (const auto& path : paths) {
-      DeleteFile(path);
-    }
-  }
-
   bool HasAnyStatisticsFiles(const TableMetadata& metadata) const {
     return !metadata.statistics.empty() || !metadata.partition_statistics.empty();
   }